Electric impulse generator for calculating machines



April 4, 1950 Original E. MUMMA 2,503,127

ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES '13 Sheets-Sheet 1 .Filed Dec. 27, 1945 'INVENTOR figfi ROBERT E. MUMMA BY &, Q ,M

Key Role HIS ATTORNEY April 4, 1950 R E. MUMMA 2,503,127

ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES Original Filed Dec. 27,1943 13 Sheets-Sheet 2 TALLY IMPULSE GENERATOR HUNDREDS LL hi 6 INVENTOR 5 r; ROBERT E. MUMMA U 16 3 5 BY C Q HIS ATTORNEY TALLY IMPULSE GENERATOR TENS April 4, 1950 Original Filed Dec. 27, 1943.

FIG. 3

.R. E. MUMMA 2,503,127

ELECTRIC IMPULSEGENERATOR FOR CALCULATING MACHINES 13 Skeete -Sheet 3 INVENTOR ROBERT E. MUMMA HIS ATTORNEY Key Rpl April 4, 1950 R; E MUMMA ELECTRIC IMPULSE GENERATOR FOR, CALCULATING MACHINES Original; Filed Dec. 27, 1943 TALLY IMPULSE GENERATOR UNITS FIG.4

Kay Roman 15 Sheets-Sheet '4 INVENTOR ROBERT E. MUMMA HIS ATTORNEY April 4,v 1950 2,503,127

ELECTRIC IMPULSE EENERA'roR- FOR CALCULATING MACHINES R. E. MUMMA 1s Sheets- Sheet 5 Original Filed Dec. 27, '1943 umah 9. mmSEa wtz: M "65550 3 5%.

INVENTOR ROBERT E. MUMMA oww/ 3.

HIS ATTORNEY April 4,1950

Criginal Filed Dec. 27; 1943 IMPULSE GENERATOR TENS- PIC-3.6

RQE. MUMMA 2,503,127

ELECTRIC IMPULSE GENERATOR F'og CALCULATING MACHINES l3 Sheets-Sheet 6 PRIMES 0" TUBE INVENTOR ROBERT E. MUMMA HIS ATTORNEY ms ATTORNEY 13 Sheets-Sheer. 7

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ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES Original Filed Dec. 27, 1945 13 Sheets-Sheet 8 IMPULSE GENERATOR THOUSANDS PRIMES "o" TUBE PRIMES TUBE FIG.8

INVENTOR ROBERT E. MUMMA BY @M HIS ATTOR NEY R. E. MUMMA 2,503,127

ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES April 4, 1950 15 Sheets-Sheet 9 Original Filed Dec. 27, 1943 o- Inn 82585 zmh mozmwzwo M322.

INVENTOR ROBERT E. MUMMA BY ,W

HTS ATTORNEY R. E. MUMMA April 4, 1950 2,503,127 ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES 1s Sheets- Sheet 1o Originai Filed Dec. 27", 1943 INVENTOR ROBERT E. MUMMA HIS ATTORNEY mmnh mmEEm umah 0 muEEm mOZ wDOIF OUKDZDIA KOF KMZMO wwJDm 5 MQ April 4, 1950 E. MUMMA ELECTRIC IMPULSE GENERATOR FOR CALCULATING'MACHINES 1s Sheet-Sheet 11 Original Filed Dec. '27. 1943v (@AZO FIG."

O-m HUNDREDS TALLY TENS TALLY @185 UNITS TALLY A M M U M a m E B 0 W R Y B o T R w A T M S U Y N F- LGVI E L RE s A L T U P m HIS ATTORNEY April 4, 1950 R. E. MUMMA ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES 1s Sheets-Sheet 12 Original Filed Dec. 27, 1943 84 b'ru fsmos T0 HUNDRED TMOUSIIDS SELEGTNELY CONDITIONED IMPULSE GENERATOR RECYCLING RELAYS SUBT RACT

RA OM M m M NE. T R E B o R R O M R TE m SW6 N AUE L Y6 RLU MP m HIS ATTORNEY April 1950 R. E. MUMMA A 2,503,127

ELECTRIC IMPULSE cmmrron FOR CALCULATING mcnmss firiginal'Filed Dec. 27,1943 1s Sheets-Sheet 1s STAGE CONTROL UNIT STAGE II INVENTOR ROBERT E. MUMMA HIS ATTORNEY Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE ELECTRIC IMPULSE GENERATOR FOR CALCULATING MACHINES Robert E. Mumma, Dayton, Ohio, assignor to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland 48 Claims.

This invention relates to an electric impulse producer for a calculating machine, and more particularly pertains to one having an impulse generator including a plurality of denominational output conductors, each of which receives in a cycle of operation an individually selected number of impulses, said impulse generator having a tally unit control operable to automatically recycle the impulse generator a selected number of times.

This is a division of my co-pending application for United States Letters Patent, Serial No. 515,718, for a Calculating device, which was filed December 27, 1943, and which issued on June 1, 1948, as Patent No. 2,442,428, and the impulse generator disclosed herein is particularly adapted to produce on each output conductor, on each of a selected plurality of cycles constituting a calculating operation as controlled by the tally unit, a selected number of impulses, each representing a unit of value of the denomination, such impulses being impressed on the denominational conductors in succession in a cycle.

The impulse generator includes a plurality of denominational banks of digit-representing electron tubes, of the gaseous discharge type, each bank of tubes being coupled in a key-controlled circuit wherein selected numbers of tubes in each bank are fired and extinguished, in succession, in

each cycle, and the banks themselves being coupled in an operative circuit wherein they are caused to operate in succession each cycle.

The number of cycles of operation of the impulse generator is controlled by the tally unit including a plurality of denominational banks of digit-representing electron tubes, of the gaseous discharge type, the tubes in a bank being coupled in a key-controlled circuit in which they are fired and extinguished in succession in response to commonly received electric impulses. An electric impulse is issued to the tally unit to commence its operation, and another is issued to it after each cycle of operation of the impulse generator. The banks of the tally unit are coupled together for successive operation. Each time a tube is fired in the tally unit, it produces an electric impulse to start an operative cycle of the impulse generator.

The keys in each bank, whether of the impulse keys of the impulse generator are used to set up 2 the multiplicand factor and the keys of the tally unit are used to set up the multiplier factor.

On operation of the impulse producer, the pattern of impulses representing the multiplicand is issued on the output conductors of the impulse generator as many times as is determined by the selected and operated keys of the tally unit.

By use of electron tubes, the successive operation of which may be made extremely fast, the impulse producer creates the selective pattern of impulses in a small fraction of the time it would take a mechanical device to accomplish the same result.

Although the produced impulses are adapted to operate any accumulator responding to denominationally produced impulses of unit value, the device is especially adapted to operate an electronic accumulator through the medium of an electronic switching and routing device particularly set out and described in my aforesaid Patent No. 2,442,428.

Therefore, it is the principal object of the invention to provide an electric impulse producer which produces a denominational pattern of electric impulses, denomination by denomination, in cycles, repeated a selected number of times.

Another object of the invention is to provide such an electric impulse producer utilizing impulse-producing electron tubes as digit-representing elements.

Another object of the invention is to provide such an electric impulse producer which has a key-controlled impulse generator unit and a keycontrolled tally unit for recycling the impulse generator a selected number of times, such unit providing, by operation of the keys, means to set calculating factors into the machine.

With these and incidental objects in view, the invention includes certain novel features of construction, circuits, and combination of parts, the essential elements of which are set forth in appended claims and a preferred form or embodiment of which is hereinafter described with reference to the drawings which accompany and form a part of this specification.

Of the drawings:

Figs. 1, 2, 3, and 4 show, respectively, the thousands, hundreds, tens, and units denominational orders of the tally unit.

Figs. 5, 6, 7, 8, 9, and 10 show, respectively, the units, tens, hundreds, thousands, tens of thousands, and hundreds of thousands denominational orders of the impulse generator unit.

Fig. 11 includes the circuits coupling the impulse generator unit and the tally unit to cause the tally unit to function a step at the conclusion of a cycle of the impulse generator unit.

Fig. 12 includes the circuits for relaying the tally unit recycling impulses to initiate cycles of operation of the impulse generator unit.

Fig. 13 shows the circuit for controlling the stages of operation of the tally unit.

The gaseous triode electron tubes used in the disclosed embodiment of the invention are of the thermionic cathode type having an anode, a cathode, and a control grid and having an internal potential drop during conduction of about 15 volts, with the electrode elements so related that a tube will fire when the grid is more positive than about 12 to 20 volts negative with respect to the cathode, depending on the anode-cathode poten tial. Circuits for heating the cathodes are indicated only conventionally. These tube characteristics are true of all the gaseous tubes shown in the drawings.

Values of potential, resistance, and capacitance,

' as given, are relative and are given as one set of values which result in proper operation with the specified tubes, but are not to be deemed the only circuit values that can be used, as the principles involved in the invention permit of different levels for these relative values and of different relative values when electron tubes of other characteristics are used. Potentials given are with respect to ground potential.

The impulse generator Figs. 5, 6, 7, 8, 9, and show, respectively, the units, tens, hundreds, thousands, tens of thousands, and hundreds of thousands denominational banks of the impulse generator. Each bank includes nine gaseous triodes (numbered 1, 2, 3, n5, n7, and ,17 p t e y representing the digits of an order of a decimal denomination, a gaseous triode, designated D, which functions as a by-pass device, and a gaseous triode, designated T, which functions to initiate the operation of another lower denominational bank of impulse generator tubes, or, in the case of the units bank, to initiate a step of operation of the tally impulse generator unit (see Figs. 1, 2, 3, and 4). The denominational banks of the impulse generator are linked together by the T tubes, or transfer tubes, and the banks are thus caused to operate serially from a higher beginning bank towards the units bank.

The number of impulses to be produced by each denomination of the impulse generator and sent to the accumulator is determined by operation of a selected digit key in selected banks of the impulse generator, the operation of a key acting to operate an associated switch to prepare certain digit tubes in each of such selected banks to operate. The digit keys are numbered in the drawings according to the digit tube with which each is associated. The selected digit tubes in a bank are fired and rendered conducting one at a time in sequence automatically after the initiating tube, which is the 1 tube, fires, and the operation of the bank is completed, after the selected tubes have fired, by the firinng of the D tube and the T tube. As each digit tube is fired, an impulse is generated on an associated denominational output conductor. In case no key in a bank is operated, the D tube of the bank will fire to bypass that bank by firing, in turn, the associated T tube. The T tube of each bank, except the units bank, by firing and becoming conducting, causes the initiating 1 tube or the D tube of the next lower denominational bank to fire. In multiplication, the highest two orders of the impulse generatorthe hundred thousands order (Fig. 10) and the ten thousands order (Fig. 9) are not used and are by-passed by connections to be described, and the initiation of an operation constituting a cycle of a multiplying operation commences with the thousands bank (Fig. 8). The only reason for the elimination oi the highest two orders of the impulse generator in multiplication is that the capacit of an accumulator of the normal commercial eight denominations might be approached in a single multiplying operation or in several multiplying operations, it the factors were large. It is to be noted, however, that, by providing such an accumulator with more capacity, such elimination of the higher denominations of the impulse generator need not be resorted to. In singlecycle operations, such as adding or substracting, all six banks of the impulse generator are used.

Each digit tube of a bank of the impulse generator is coupled, as has been said, to a common output conductor representing that bank, and, as each digit tube associated with such an output conductor is fired, it produces a positive**electric potential impulse on said output conductor which may be utilized to actuate an accumulator. The impulses on a particular output conductor thus have denominational significance and, in one type of calculation, are routed in a given cycle of operation of the impulse generator to the proper denomination of an accumulator, automatically, by an electronic denominational impulse distributor according to the stage of the calculation, as described in the before-mentioned Patent No. 2,442,428.

The key switch associated with each digit key controls the operation of the digit tubes of the associated bank to produce the selected number of impulses, and the associated keys numbered 1'1! 2, 3, 4, 5. n6, 7, and 9 each control in a cycle the production of an equivalent number of impulses.

The units bank (Fig. 5) of the impulse generator group of banks will be used as an example of a typical bank of the group, as in essence all of the banks of the impulse generator are the same, with the exception that the D and T tubes of the units bank have the same anode supply source as the associated digit tubes, whereas, in the higher banks, a separate anode potential supply source is provided for the T tubes.

Referring to the units bank (Fig. 5), the anodes of all the tubes, including the digit tubes and the D and T tube, are connected to a source of potential of 85 volts positive through terminal 50 and resistor 46 of 1,000 ohms. Terminal 50 is common to all the banks of the impulse generator (see also Figs. 5, 7, 8, 9, and 10) and obtains its potential through a resistor 5| (Fig.

11) of 4,000 ohms and a resistor 53 of 25 ohms on the closing of switch 52. The cathodes of each of the digit tubes of Fig. 5 are connected on one side to ground through a resistor such as resistor 41 of 25,000 ohms and are normally connected on the other side to a negative 170-volt conductor 48 through a resistor like resistor 54 of 60,000 ohms, a switch like switch 55, a point like point 56, and a resistor like resistor 51 of 100,000 ohms. Points like point 56 are coupled also to the negative supply conductor 48 through a capacitor like capacitor 58 of .002 microfarad. The cathode of each digit tube is connected, through a capacitor like capacitor 59 of .005 microfarad, to an output conductor 60, which is connected to terminal I08 and grounded through resistor of 100,000 ohms. It will be apparent that, when any one of these digit tubes fires and is rendered conducting, due to the resistance in the cathode supply, there will be a positivewise in potential of the cathode, which will be impressedthrough the capacitor to the output conductor, and consequently said output conductor 00 and terminal I00 receives a positive potential impulse signal for each digit tube of the bank, as it fires and becomes conducting. Terminals I (Fig. 6). I (Fig. 7), III (Fig. 8), H2 (Fig.

'9), and H8 (Fig. 10) are the output terminals for the tens, hundreds, thousands, ten thousands;

. a resistor 62 of 500,000 ohms, and a resistor 63 of 100,000 ohms. Thus each digit tube grid is normally heavily biased against conduction. The resistors corresponding to resistor 63 for the grids of the digit tubes of higher value-for instance, resistor 51 associated with the 2 tubenormally constitute part Of'the cathode supply circuit of the next lower value tube.

Switches, such as switch 55, in the normal unoperated condition as shown in the drawings, connect the cathode of its associated tube with the control grid of the next higher tube, and hence, for instance, if the 1 tube fires, the rise in its cathode potential is impressed in part through resistor 54, switch 55, point 56, resistor 65, and resistor 66, and will be sufficient to overcome the controlling bias on the 2 tube grid and cause it to fire and become conducting. As each digit tube fires, the initial current through it is high during the time the capacitor connecting the cathode to the output conductor 60 is being charged, and the common anode resistors such as resistors 46 (Fig. 5) and 5| and 53 (Fig. 11) cause the anode of the tube commencing to conduct to drop sharply in potential, momentarily, which potential drop is impressed on the anodes of all the associated digit tubes, and, in

the case of the units bank, on the anodes of the D tube and the T tube as well. Any conducting digit tube will be extinguished as another tube of the bank fires, because, if a tube has been conducting, the capacitor connecting its cathode to the output conductor will have been charged, and, as its anode drops in potential due to another tube firing, its cathode will be sustained temporarily at a relatively high level, and the anode potential will fall below the potential of the cathode, causing the tube to deionize, allowing the control grid to resume control. This method of extinction of a conducting tube by means of causing its anode potential to drop below cathode potential when another tube on the common anode supply circuit fires has been disclosed in my co-pending application for United States Letters Patent, Serial No. 395,995, which tube will extinguish the 1 tube or any other digit tube. However, when the 1 tube in a bank fires, the potential of terminal receives a momentary dip which is impressed on the anodes of all tubes in other banks connected thereto. This eflect on other banks will extinguish any conducting digit tube therein.

If no key in a bank is operated, that bank is by-passed as far as the digit tubes are concerned, and only the D tube of that bank will fire, followed by the firing of the-T tube. The firing of the T tube ends the operation of the bank and passes on an impulse to the next lower bank, which impulse is created by the rise in potential of its cathode as conduction commence in the tube. The impulse generator is arranged in this disclosure to operate bank by bank in sequence from the highest order bank to the lowest order bank, to prevent any interference in transfer of carry-over data in the accumulator,- and therefore the T tube output of any particular bank is connected to the input conductor of the next lower bank, except that the units bank output terminal H5 is connected to the tally unit operation initiatingunit relay (Fig. 11), to be described, either to initiate a recycling of the whole operation of the impulse generator or to cause it to cease operating, as at the end of a calculation.

To commence the operation of a bank of the impulse generator, provision has been made that. if no key in the bank is operated, the normally controlling potential bias of the D tube is relieved, or primed, to near the firing point, and, if a key in the bank is operated, the normally controlling bias of the 1 digit tube is relieved or primed.

' To actually start the operation of a bank, a

positive potential impulse must be impressed on an input terminal, such as terminal 18 (Fig. 5), serving the units bank, which impulse is impressed through capacitors 600 of .0001 microfarad and 01 of .001 microfarad, capacitor 660 being connected to grid bias point of the 1" tube and capacitor 01 being connected to grid bias point 69 of the D tube. The positive potential impulse starting an operation of the bank, therefore, tends to cause both the 1 tube and the D tube to fire and become conducting.

The priming of the D tube when no key is depressed is arranged to make it and not the 1 tube responsive to the starting impulse. When a key is depressed, the 1 tube is arranged to be responsive to a starting impulse, and not the D tube. Still taking the units bank (Fig. 5) as an example, the selective priming potential for the D and 1 tubes of the bank is obtained from ground through resistor 10 (Fig. 5) of 100,000 ohms and switch H. A key detent bar 12 is normally maintained in the position shown in Fig. 5 by a spring 13, and studs 14 thereon hold switch H against the contact 16 conveying ground potential through to point 69, priming the D tube. If a key in the bank is operated, as, for instance, the 4 key, a cam surface 89 thereon operates against the surface 90 inside the key slot to move the bar 12 to the left, which moves switch II to contact 9|, thus, through conductor 11, priming point 98 and thereby the 1 tube grid so that the 1 tube will respond to a starting impulse and the D tube will not respond. The input starting impulse impressed on terminal I8 is adjusted to differentiate between the primed and unprimed tubes.

Another function of the operation of any key is to break the normal connection between the cathode of its associated tube and the control grid of the next higher tube in the bank and to connect the said cathode of the tube associated with the key to the control grid of the D tube. Thus, digit tubes in abank, if any are selected by operation of a key, will fire automatically one at a time in sequence; beginning with the 1 tube and ending with the tube associated with the operated key, impressing 'on the associated output conductor the number of impulses represented by thatkey. Thereafter the D tube is fired, followed by the T tube, to conclude the operation of the bank.

For instance, if key "1 is operated, contact It is disconnected from ground and switch 85 will bridge the lower contacts and connect the cathode oi the 1 tube to conductor 93, which leads to point 69, which is in the grid circuit of the D tube. As has been explained earlier herein, the D tube is given a sufficient bias that it will not respond to impulses applied to it over terminal 18 unless it has been primed by having point 69 in its grid circuit connected to grounded contact 16. Even though the prime has been removed 8 of higher order banks receive their anode potential through a common point Ill (see also Fig. 11) each through-a resistor, like resistor III,

of 250,000 ohms. Each resistor, like resistor I", Is shunted by a capacitor, like capacitor Ill of .005 microiarad, in series with a resistor, like resistor I of 5,000 ohms. Referring to Fig. 11, terminal I is connected to an 85-volt potential source through a resistor III of 10,000 ohms and is connected to ground through a resistor I of 8,000 ohms. Therefore, the T tube of the tens bank when fired stays conducting until tube I23 (Fig. 11) fires and becomes conducting, as will be explained, and the T tubes of the banks higher than the tens bank will be extingished on the event of the T tube of the next lower bank firing,

by the operation of the 1 key, the D tube will operate after the last tube of the series to fire because the potential impulse which it receives over conductor 93 from the last tube to fire, of

the digit tubes selected, is great enough, even in the unprimed condition of the D tube, to cause the grid to lose control and consequently cause the firing of the D tube. The capacitors asdue to the common anode resistance (see Fig. 11) and the individual cathode-ground capacitors. The T tube of the units bank is extingished by the event of the firing of the tube I I5 (Fig. 11) which event is initiated by reason of the cathode rise in potential of the units T tube (Fig. 5) being impressed on terminal II5 (Figs. 5 and 11).

It will be understood, then, that the banks of the impulse generator fire in sequence from the higher orders towardthe units order, the digit tubes in banks in which keys have been operated firing sequentially in the bank, followed by the firing of the D tube and the T tube. In the case sociated with the negative potential supply cir-' cult of the grids of the digit tubes in a bank higher than the 1 tube, such as capacitor 58 connecting grid bias point 56 of the "2 tube to the negative 1'70-voltconductor 48, delay, for a short period while charging, the firing of the next digit tube after the commencement of conduction in the. preceding tube. Consequently, such capacitors, as capacitor 58, control the timing of the output impulses from the impulse generator, and, with the valuesoi circuit elements and potentials given, the interval involved between any two output impulses in the same: bank is of the order of .0001 second. It is apparent, however, that timing adjustments may be made to satisfy any desired speed of operation up to the limit of the tube response.

The D tube (Fig. 5) obtains its cathode potential on one side from ground through a resistor 94 of 25,000 ohms and on the other side from the negative 1'70-volt conductor 48 through resistors 95 of 60,000- ohms and 96- of 100,000 ohms. The cathode is also'connected to ground through capacitor 91 of .001 microiarad to cause the drop in the anode supply conductor to extinguish the last digit tube to fire on the event 'of the firing ofthe D tube. The value of grid resistor I is 50,000 ohms, and the value of resistor 99 is 100,000 ohms; Point I" is connected to the grid of the T tube through resistor Ill of 50,000 "ohms to furnish it with its normal controlling bias. The cathode of the T tube obtains its potential from ground through resistor ll! of 25,000 ohms, which is in parallel with a capacitor I02 of .001 microfara'd, and through its connection over resistor 438i to negative I'm-volt conductor 48. The rise in potential of .points Hill as tube D fires automatically fires the T tube. Capacitor I03, of .005 microfarad, is a timing capacitor, delaying the firing of the T tube for an interval after the firing of the D tube.

' The anode potential supply of the T tubes in the banks higher than the units bank are separate from that of the digit and .bes of the bank. Referring to Fig. 6 as typical, the T tubes of a bank in which no key has been operated, then only the D tube and the T tube of that bank will be rendered conducting in' succession.

At'the end of a calculating operation, a key release solenoid for each bank may be activated and return the keys to home position under the action of individual springs, such as spring 0 (Fig. 5).

The operation of the impulse generator in single entries into an accumulator, such as in addition and subtraction operations, is initiated by a potential impulse applied to terminal 88 of the hundred thousands bank (Fig. 10). The output from its T tube at terminal 81 is connected to the input terminal 86 of the ten thousands bank (Fig. 9). The output terminal 85 of the T tube of the ten thousands bank is connected to the input terminal 84 of the thousands bank (Fig. 8). The output terminal 83 of the T tube of the thousands bank is connected to the input terminal 82 of the hundreds bank (Fig. '7). The output terminal BI or the T tube of the hundreds bank at terminal 8| is connected to input terminal ll of the tens bank (Fig. 6). The output terminal l9 0! the T tube of the tens bank is connected to the input terminal 18 of the units bank (Fig. 5)

In calculating operations requirin a succession of entries into the accumulator, such as multiplying, the higher two banks of the impulse generator are by-passed, as has been said, and initiation of a multiplying operation is commenced by impressing the initiating positive impulse on terminal 84 (Fig. 8),, as will be explained.

It is evident that the impulse generator is not restricted in principle to the decimal numerical base, as any number of digit tubes may be placed in each bank. Neither is the impulse generator restricted in the number of banks used.

The impulse generator is recycled as many.

times as selectively determined by the tally imnominational orders of an accumulator.

The closing of switch 52 (Fig. 11) prepares the impulse generator for operation by supplying anode potential to the digit tubes.

Relaying end of operation impulses from impulse generator to tally unit Tubes H6, I22, and I23 (Fig. 11) prepare the impulse generator for another cycle and initiate operation of the tally unit.

Each of the tubes H6, I22, and I23 (Fig. 11) has its cathode grounded on one side through a resistance, like resistance I25, in parallel with a capacitor like capacitor I26. ResistorsI25, I21, and I28 are, respectively, of 50,000 ohms, 25,000 ohms, and 60,000 ohms, and capacitors I26, I29, and I30 are, respectively, of .004 microfarad, .0005 microfarad, and .002 microfarad. On the other side, each of the cathodes is connected to a negative 170-vo1t conductor I44 through a resistor or resistors, said resistors having the following values: resistor I56--l50,000 ohms, resistor I33-25,000 ohms, resistor I6l--150,000 ohms, and resistor I62-500,000 ohms. The cathode of tube I I6 is coupled through a capacitor I 3| of .0001 microfarad to point I32 in the grid circuit for tube I20. A resistor I58 of 250,000 ohms connects point I32 to point I42 in the grid potential supply circuit of tube I22; the cathode of tube I22 is connected through resistance I33 to grid bias point I43 of tube I 23; and the cathode of tube I23 is connected to input conductor I34 for the relay tubes I50, II, I52, and I53, each associated with a denomination of the tally impulse generator unit to be discussed later. Capacitor I34I is provided as a time delay and may be of .01 microfarad. The grid of tube H6 receives its normal bias potential and firing potential from the cathode of the T tube of'the units bank of the impulse generator through terminal H5 (Figs. 5 and 11), which has a normal potential of about 22 volts negative, when the T tube is not conducting being connected to ground through 60,000-ohm resistor 431 and connected to the-negative ITO-volt supply conductor 48 through 100,000-ohm resistor 438I. The grids of tubes I22 and I23 (Fig. 11) receive their normal controlling grid bias potential from points I42 and I43, respectively, each being positioned in a potential divider located between negative 1'70- volt supply conductor I44 and ground. Resistors I59 and I60 are of 40,000 ohms and 100,000 ohms respectively, and resistors I33 and I6I have been specified earlier herein. The anodes of tubes I22 and I23 receive potential from point I20, the anode of tube I 22 being isolated by resistor I63 of 7,500 ohms. Suitable values for resistors I55 and I51 are 500,000 ohms and 50,000 ohms respectively. With such circuit values, the tubes H6, I22, and I23 fire one after another when the cathode potential rise, resulting from the units bank impulse generator T tube firing (Fig. 5), is impressed on terminal II5 (Figs. 5 and 11). The circuit values of capacitance and distributed inductance incident to normal wiring, and the combination of low resistance in the anode supply circuit with high resistance in each tubes cathode supply circuit shunted by a capacitor immediately causes each of the said tubes H6 and I23 to self-extinguish after it fires, as the initial high current flowing through a tube during the time the cathode capacitor is charging causes an ensuing oscillatory rise in cathode po tential as the high tube current is abruptly terminated, which rise overshoots the anode potential. Tube I22 is extinguished on the firing of tube I23 as the common anode supply point drops in potential. Therefore, each of these tubes H6, I22, and I23, after firing, is reset ready for another operation.

Tubes I50, I5I, I52, and I53 are individually primable gaseous triode tubes, used'as relays, and are each arranged in a circuit having selfextinguishing action similar to the circuits of tubes H6 and I 23. Suflicient anode-cathode potential is given constantly to all of the tubes I50, I5I, I52, and I53 to maintain conduction therein, but the grids of the tubes are normally biased to prevent firing even when a positive potential impulse over input conductor I34 is impressed commonly on the grids, each grid being connected to conductor I34 through a capacitor of .00025 microfarad, like capacitor I65, in series with a resistor of 50,000 ohms, like resistor I66. The grid bias potential is supplied to each grid individually at a point, like point I61, througha resistor like resistor I68 of 250,000 ohms, and a terminal like terminal I69 (see also Fig. 13). Terminal I69 (Fig. 13) is connected to the potential supply circuit of the cathode of tube I920, and the potential of terminal I69, due to the resistance in the cathode potential supply of tube I920, is raised when tube I920 is conducting as compared to when tube I920 is in non-conducting condition. Such rise in potential primes the grid of tube I50 (Fig. 11) to a point where it is fired by an impulse impressed on conductor I34. In a similar manner, terminals I1I, I12, and I13 (see also Fig. 13) are similarly primed by conduction, respectively, in tubes 2010, 2060, and 2050. More will be said about tubes I920, 2010, 2060, and 2050 in connection with the description of the stage control unit, of which tubes I920, 2010, 2060, and 2050 are a part.

The anodes of tubes I50, I5I, I52, and I53 (Fig. 11) receive their potential supply from volt positive source I through resistor I15 of 50,000 ohms and resistor I16 of 1,000 ohms, after the closing of switch I14. Point I11 is grounded by resistor I18 of 15,000 ohms in parallel with ca- ,pacitor I19 of .01 microfarad introduced into the circuit to insure stability of potential supply. Each cathode is grounded through a resistor like resistor I80 of 60,000 ohms shunted by a capacitor like capacitor IBI of .001 microfarad, and each is connected to negative 1'10-volt conductor I83 through a resistance, like resistance I 82 of 250,000 ohms. The stated values of circuit elements of resistance and capacitance with the distributed inductance in normal wiring will cause any one of the tubes to immediately self-extinguish when fired due to the oscillatory rise in potential of the cathode, as has been explained for other tubes. Each time the impulse generator completes a cycle, that one of the tubes I50, I5I, I52, and I53 which is primed, fires and self-extinguishes, passing on a positive potential impulse on the associated one of the cathode output terminals I85, I86, I81, and I88, to cause a step of operation of an associated denomination of the tally unit impulse generator, as will be described.

Tally unit for controZZing number of impulse generator cycles in each of selected stages 88 (Figs. 10 and 12) for initiating multiple-cycle impulse generator operations and single-cycle impulse generator operations, respectively. Such 11 initiating impulses originate in the tally counting unit shown in Figs. 1, 2, 3, and 4 under control of the circuits of Fig. 13, and are relayed by the circuits of Fig. 12 to the selected one of terminals 88 and 84.

Referring to Fig. 12, gaseous triode electron tube 200 relays recycling impulses from the tally unit impulse generator (Figs. 1-5) to the thousands bank of the impulse generator. The cathode of tube 200 is connected by conductor 201 to terminal 84 (see also Fig. 8), and, each time tube 200 fires, terminal 84 is given a positive potential impulse. Gaseous triode electron tube 202 relays recycling impulses from the tally unit impulse producer to the hundred thousands bank of the impulse generator. The cathode of tube 202 is connected by conductor 203 to terminal 88 (see also Fig. 10). and, each time tube 202 fires, terminal 88 is given an impulse.

Tube 200 is self-extinguishing and is supplied with 85 volts anode potential by source terminal 204, through resistor 205 of 10,000 ohms and resistor 208 of 1,000 ohms. Point 201 is coupled to ground through resistor 208 of 25,000 ohms in parallel with capacitor 209 of .05 microfarad. The cathode is grounded through resistor 210 of 75.000 ohms in parallel with capacitor 211 of .00015 microfarad. The grid is connected to biasing point 212 through resistor 213 of 50,000 ohms and resistor 214 of 500.000 ohms. Point 212 normally is given a controlling bias potential of about 20 volts negative by being connected to ground on one side by resistor 215 of 40.000 ohms. conductor 216, switch 211, and switch 218, and connected on the other side to a negative 170- volt source through a resistor 2 I 9 of 300.000 ohms. Tube 202 has anode and cathode potential supply circuits similar to tube 200 except that, normally, point 220 is connected to the ground 223 through a resistor 222 of 400,000 ohms, making the normal controlling bias of its grid over 100 volts negative. Therefore, with neither key 225 nor 22B operated, an impulse of approximately 30 volts positive impressed on the grids of tubes 200 and 202 from point 224. through capacitors 244 and 243, will fire only the tube 200 and relay the impulse through terminal 84. initiating the operation of a cycle of the impulse generator at the thousands bank. However, if either add key 225 r subtract key 226 is operated. the connection of the point 212 to ground 221 is broken. which is supplanted by connection to ground 221 throu h resistor 228 of 400.000 ohms. preventing tube 200 from firing on a 30-volt ositive si nal. On the other hand, point 220 is connected to ground 221. rendering tube 202 responsive to a 30-volt positive signal from point 224. which relays a cycling impulse to the hundred thousands order of the impulse enerator instead of to the thousands order. In this manner. the tvpe of calculating operation determines the start n point in the impulse generator for a cvcle of oneration thereof. It is to be noted that add key 225 and subtract key 226 also may be utilized to control various other units of a calculating machine. as set out in my co-pending a plication Serial No. 515,718, now Patent No. 2,442,428 referred to.

Gaseous triode electron tubes 230. 231. 232. and 233 are relays. respectively. for the impulses produced by the thousands, hundreds. tens. and units banks of the tally impulse unit shown in Figs. 1, 2. 3, and 4. As anv one of these tubes 230 to 233 fires, a rise in cathode potent al ensues, sending a positive impulse on common cathode conductor 234 to fire either tube 202 or 200, whichever is selected. The relay tubes 230 to 233 are self-extinguishing. All the anodes receive a potential from a common -volt positive source terminal 235 through resistor 236 of 7,500 ohms, point 231, and resistor 238 of 1,500 ohms. Point 231 is coupled to ground by resistor 239 of 15,000 ohms in parallel with capacitor 240 of .01 microfarad. The cathodes of tubes 230, 231, 232, and 233 receive their potential from conductor 234, connected to ground through resistor 241 of 50,000 ohms in parallel with capacitor 242 of .001 microfar-ad. Output point 224 is coupled electrostatically to the grids of tubes 202 and 200 by capacitors 243 and 244, each of .00005 microfarad. The grids of tubes 230-233 are each con nected through a resistor like resistor 245 of 50,000 ohms, a point like point 246, and a resistor like resistor 241, to conductor 248, which is given a controlling potential of about 14 volts negative. being connected through resistor 249 of 15,000 ohms to ground and being connected through resistor 250 of 200,000 ohms to negative 200-volt source terminal 251.

Each grid point like point 246 is coupled through a capacitor of .0001 microfarad, like capacitor 252, to a terminal like terminal 253. Terminal 253 is connected to the output conductor of the thousands bank of the tally impulse generator (Fig. 1), terminal 254 is connected to the output conductor of the hundreds bank (Fig. 2), terminal 255 i connected to the output conductor of the tens bank (Fig. 3), and terminal 256 is connected to the output conductor of the units bank (Fig. 4). These terminals, when given apositive impulse, will fire the associated one of relay tubes 230233 and impress a positive impulse on conductor 234. After each relay tube fires, it will be self-extinguished because of the circuit elements described, in the same manner as the other self-extinguishing tubes heretofore described.

Circuit controlling the stages of a calculating operation Referring to Fig. 13, there is shown a plurality of pairs of gaseous electron tubes, one of each pair controlling an associated stage priming group of the conductors which may be used to control the routing of impulses issuing from the impulse generator shown in Figs. 5, 6, '7, 8, 9 and .10, and the other tube of each pair controlling the corresponding stage of the tally unit impulse generator shown in Figs. 1, 2, 3, and 4.

The stages of a calculating operation will be designated I, II, III, and IV, stage I being that in which a selected multiplicand as set up by the keys of the impulse generator is produced as a pattern of impulses as a number of time as though multiplied by the units denomination of the selected multiplier as set up on the keys of the telly unit impulse generator, to be described. Addition or subtraction is performed as a multiplication by one, and, therefore, addition or subtraction is a stage I calculation.

A start key260 (Fig. 13), when operated, closes switch 261 to ground the conductor 282. A priming electron tube 263 of the gaseous triode type is fired by having the potential of its grid, normally maintained at about 40 volts negative by being connected through 50,000-ohm resistor 264. point 285, resistor 260 of 500,000 ohms to point 261, which point is connected to ground through resistor 288 of 60,000 ohms and to negative -volt supply conductor 269 through resistor ing will be traced in what follows.

- 13 210 of 200,000 ohms, raised to the firing point by reason of its grid bias point 265 being coupled to said conductor 262 through capacitor 21I of .00025 microfarad. The cathode of priming tube 203 is grounded on one side through a resistor 212 of 75,000 ohms in parallel with a resistor 213 of 5,000 ohms in series with capacitor 214 of .001 microfarad, and is connected on the other side to the negative 170-volt conductor 269 through resistor 288 of 375,000 ohms. The anode is supplied with potential by being connected by conductor 215 to conductor 216, serving the tubes 2050, 2060, 2010, and I920 with anode potential. Conductor 216 is connected through resistor ml of 22,500 ohms, point 282, and resistor 283 of 100 ohms to an 85-volt positive source of potential. Point 204 is grounded through resistor 285 of 7,500 ohms and capacitor 286 of .01 microfarad in parallel with resistor 281 of 15,000 ohms. Under these circumstances, when the Start" key switch is closed, the priming tube 263 will fire and become conducting, the capacitor 214 will charge, and the potential of the cathode of tube 263 will thereafter rise. That rise in cathode potential is used for priming the grid of a selected one of the tubes 2050, 2060, 2010. and I920. In the adding position of switch 29I, the tube I920 is primed. In the multiplying position of switch 29I, that one of tubes 2050, 2060, 2010. and I920, as determined by detent-operated switches 306309, i primed. The circuits for such prim- The common anode supply conductor 216 for the priming tube 263, and tubes 2050, 2060, 2010, and I920. will receive a drop in potential as any of the tubes 2050. 2060, 2010, and I920 fire and become conducting. because these last-mentioned tubes have their cathodes coupled electrostaticallv to round. and, while the cathode-ground capacitor is charging on commencement of conduction in the associated tube, the potential of conductor 216 drops momentarily to within about 15 volts of ground. At this time, the priming tubes cathode potential is far above ground by reason of its cathode-ground capacitors having been charge 20 and I920 becomes conducting,

The add-subtract and multiplyin key 290 is rovided with two switches 291 and 292. Swit es 79 and 292 on the upper contacts prepare the tally impulse producing device for an adding or s btracting operation and on the lower contacts pre are that device for a multiplying operation.

In an adding operation, the cathode of the priming tube 263 is connected throu h point 293.

resistor 294 of 500,000 ohms, switch 29I. in p er osition. conductor 295. points 296 an 291. osistor 298 of 500,000 ohms, point 299. and resistor 300 of 50,000 ohms to the grid of tube I920. primin it. as tube 263 conducts. Terminal 314 (see also Fig. 4) connected to point 296 also primes the 9 t be of the units bank of the tallv im ulse generator, which 9 tube will thereafter be fired by the firing of tube 280 (Fig. 13). causing a potential rise on terminal I85, as will be explained more in detail.

In multiplying operations, that one of tubes 2050. 2060. 2010, and I920 to be primed depends on what multiplier is set up on the keys of the tally impulse generator (Figs. 1, 2, 3, and 4),

14 switching being provided so as to prime that stage control tube of the unit of Fig. 13 which is associated with the highest denomination significant digit of the selected multiplier number. Thus, if the multiplier is 5670, stage IV is primed; if the multiplier is 672, stage III is primed; if the multiplier is 54, stage II is primed; and if the multiplier is 8," stage I is primed. The operation of a key in a bank of the tally impulse generator (Figs. 1, 2, 3, and 4) moves an associated detent bar, that for the thousands bank being 30I (Figs. 1 and 13), that for the hundreds bank being 302 (Figs. 2 and 13), that for the tens bank being 303 (Figs. 3 and 13), and that for the units bank being 3043 (Figs. 4 and 13). The potential of switch point 305 (Fig. 13 is normally carried through detent bar operated switches 306, 301, 300, and 309 to dead contact 3I0. The highest denominational key of the tally impulse generator that is operated in a given calculation moves the associated detent bar, switching the connection of point 305 to the associated stage tube. Thus, if a thousands bank key is operated in the tally impulse generator unit (Fig. 1), switch 306 (Fig. 13) will be moved by the detent bar 30I to contact 3, connected through resistor 3I2 of 50,000 ohms to the grid bias point 3I3 of tube 2050, representing stage IV of a calculating operation. The effect of movement of detent bars 302, 303, and 304 similarly makes contact with switch points 3I5, 3I6, and 3I1, leading, respectively, to the grid bias points 3I8, 3I9, and 299, respectively, of tubes 2060, 2010, and I920. It is apparent that the highest denominational switch of switches 306, 301, 308. and 309 that is operated carries the potential of point 305 to its associated tube to the exclusion of the lower stage tubes. Thus, with the key 290 set to multiplying position, tube 263. upon firing, primes the stage tube associated with the highest significant multiplier digit.

The cathode of each of stage control tubes 2050. 2060, and 2010 is given its potential supply by being connected to ground on one side through a resistor of 25,000 ohms, like resistor 320, in parallel with a capacitor of .002 microfarad, like capacitor 32I, and on the other side to negative volt conductor 269 through a resistance of 15,000 ohms, like resistor 322, a point like point 323, a resistor of 7,500 ohms, like resistor 324, a point like point 325, a res stor of 15,000 ohms, like resistor 326, a point like point 321, a resistor of 2.500 ohms like resistor 328, a point like point 329, and a resistor of 50,000 ohms like resistor 330.

The cathode supply of tube I920 is slightly different. The difference in the arrangements of resistors in the cathode supply of tube I920, as compared to the tubes 2050,2060, and 2010 relates to its priming action on the key release tube 2300 as well as its firing effect upon its companion tube 260.

The resistances leading from the cathode of a stage control tube-for instance, tube 2050-to the negative 1'70-volt conductor 269 form a multiple potential divider. At point 323, a connection is made through a resistance of 100,000 ohms, like resistor 33I, a paint, like point 332, and a resistance of 50,000 ohms, like resistor 333, to the grid of the companion tube 211 of the pair constituting stage IV. Conduction in tube 2050 raises the normal controlling potential bias of tube 211 to fire it after the charging of grounded delay capacitor 330 of .005 microfarad. Point 325 is given a lesser potential rise as tube 2050 commences conduction, which is impressed on te"- 

